1. Field of the Invention
The present invention is related to an illumination apparatus for single-base lamps in which single-base type light-emitting means, such as fluorescent lamps or the like having a base plug at one end thereof, are mounted to carry out illumination, and in particular to an improvement of the mountability of arranging a plurality of light-emitting means, an improvement of the diffusivity of the light-emission beam emitted by the mounted light-emitting means, and an improvement of the productivity.
2. Background Art
As is well known, HID lamps (High Intensity Discharge lamps) are frequently used for illuminating sport facilities and business establishments (stores) and the like which have a relatively large-scale space. These HID lamps are preferred because the light beam of each lamp has large characteristics due to the fact that a light-emission operation based on mercury atoms is an operation carried out in the visible light range.
However, because these HID lamps have the property of emitting light at high temperatures, it takes time for the brightness to stabilize after current is passed therethrough. Further, in order to turn these lamps on again after they have been turned off temporarily, the lamps need to be returned to such temperature and can not be turned on immediately, and because of such characteristic defects, these lamps need to be replaced with other light-emitting means.
In this regard, the present applicants proposed the illumination apparatus shown in Patent Document 1(Japanese Laid-Open Patent Publication Number 2000-164027), for example. This illumination apparatus uses fluorescent lamps which are so-called fluorescent lights as light-emitting means. Further, in this illumination apparatus, a fitting base plug is provided in a base socket for a mercury lamp, a plurality of base sockets are arranged on an opposite surface, and fluorescent lamps are mounted in these base sockets to carry out illumination. The fluorescent lamps are single-base type lamps having screw type base plugs at one end thereof which achieve an improvement from the aspect of energy savings because the power consumption due to light emission caused by fluorescent action is remarkably low.
In a single-base type fluorescent lamp, the base plug frequently uses a general E26 base in order to make the fluorescent lamp interchangeable with a bulb lamp. Further, various lamps having different shapes and sizes such as length, thickness and the like due to requirements such as light-emission performance and decorativeness and the like are manufactured.
For this reason, at the illumination apparatus side, there needs to be a correspondence with such various fluorescent lamps having different sizes and shapes. Incidentally, in the publication mentioned above, because a plurality of base sockets are arranged close together, in the case where round fluorescent lamps having large diameters are used, for example, the mounting regions of adjacent base sockets will overlap, and this interference will make it impossible to mount such lamps.